Direct fired air heater



Aug. 8, 1950 C. C. OWEN DIRECT FIRED AIR HEATER Filed Oct. 19, 1946 Z'moentor W 0 m M u/ C Patented Aug. 8, 1950 DIRECT FIRED AIR HEATER Charles 0. Owen, Toledo, Ohio, minor to Suri'ace Combustion Corporation, Toledo, Ohio, a

corporation of Ohio Application October 19, 1946, Serial No. 704,444 4 Claims. (01. 158-28) 1 This invention relates to a portable combustion unit for use out-of-doors as in railroad yards and on highways for producing highly heated gases for miscellaneous heating operations. The object of the invention is to provide a combustion unit which shall be well adapted for such use and which shall be relatively simple in construction. For a consideration of what I consider to be novel and my invention, attention is directed to the following specification and the claims appended thereto.

In the accompanying drawing forming part of this specification, Fig. l is a partial axial section and side elevation of the improved combustion unit without any showing of the supporting means on which the unit will ordinarily be mounted such as a wheeled vehicle which will also support the various adjuncts, such as, fuel tank, power-operated blower, etc., for operating the unit. Fig. 2 is a fragmentary sectional view on line 2-2 of Fig. l.

The improved combustion unit comprises a combustion chamber defined by an openended metal cylinder 9 arranged with its front end within a cylindrical air casing III to receive air therefrom. The discharge end of said cylinder is indicated at H and extends substantially alrtight through the adjacent end wall l2 of an enlarged portion it of the air casing; The broken lines 13 at the discharge end ll of the cylinder 9 diagrammatically represent an attachment for conducting the hot gases to the particular place of use of such gases.

The air casing ID has a radially enlarged portion It to form a channel wherein a whirling motion may initially be imparted to the air supplied to the casing, the whirling motion being produced by discharging the air tangentially into said channel from a tangential air inlet II, the air being delivered to said inlet under pressure and coming from a power operated blower, not shown. The air will whirl not only in the channel provided by said enlarged portion [6 but also in the more restricted annular space 31 between the casing to and the cylinder 9. The whirling air will, of course, result in rapid heat exchange between the air and the hot walls of the combustion cylinder thereby protecting the walls of the latter against overheating and at the same time preheating the air before it comes in contact with the fuel which is to be burned in the manner hereinafter described. The combustion cylinder 9 is coaxial with the air casing I0 and at its inner end is heldin that relation by spacins rods l4.

The front end wall of the air casing is indicated at ii. A burner I9 is mounted on the outside face of the wall 15 coaxial with a central opening in the wall. The fuel will ordinarily be gasoline because of its ready availability in the field but other fluid fuels may be used. In the case of liquid fuel, the preferred burner comprises an atomizing nozzle 2| mounted at the small end of a conical hood 20 which straddles the central opening in the wall l5, this hood also carrying a spark plug 24 for igniting the fuel. Partly to help to keep the nozzle cool but primarily to aerate the atomized fuel in the said hood for ready ignition, a stream of air from an air pipe 22 envelops the body of the nozzle and thence enters the conical hood 2!} through an annular passage about the discharge end of the nozzle. The air pipe 22 connects with a small air outlet 23 in the air casing l0.

A metal shell [8 in the form of a truncated cone is arranged coaxial with the combustion cylinder 9 with its large end within the latter in radially spaced relation to provide an air passage therebetween for the entry of air into said cylinder from the air casing l0 and with its small and facing the burner l9 but axially spaced from the wall l5 of the air casing to provide an air gap therebetween for the entry of air into said shell from said air casing Ill. The space encompassed by shell l8 constitutes a primary combustion zone wherein the already ignited fuel from the burner I9 is burned as completely as possible before it enters the secondary combustion zone formed by the cylinder 9.

To permit control of the amount of air entering the front end of the shell IS, the latter is mounted for movement in an axial direction, the mounting comprising a sleeve 26 which projects into the front end of the cylinder 9 in a nontight manner so as to permit axial adjustment. Front and rear spacer rods 21 and 28 serve to fixedly support the shell within the sleeve. The sleeve is axially adjusted by screw rods 29 which extend through threaded openings 30 in the front wall l5 of the air casing, the rods being shown as turnably anchored to the front spacing rods 21. To permit control of the amount of the air which enters the cylinder 9 by way of the annular passage around the shell [8 there is provided in said passage an axially adjustable annular damper 32. Although the damper is slidably supported by the sleeve 26, it is nevertheless held in operative position by a plurality of screw rods 33 which extend through threaded openings 34 in the front wall ii of the air casing. Because 3 the air in the space 81 between the air casing and the cylinder whirls as it flows axially. it can-- tinues to whirl to greater or less degree as it flows into the front or small end of the shell ll with the result that there is accelerated burning of the fuel as it moves through the shell. 7

The core of the gases advancing into cylinder 9 from the shell l8 may require special aeration to insure complete combustion-of the residual fuel and this may be accomplished by arranging a radially discharging air nozzle 40 coaxial with the cylinder 9 some distance away from the discharge end of the shell 18. Air may be supplied to this nozzle by an air supply pipe ll shown as extending diametrically across the cylinder 8 to receive air from the enlarged portion 16 of the air casing Ill. The front end of the air nozzle 40 is desirably provided with a target plate 42 for deflecting the core of the oncoming buming gases in a radial direction to produce turbulence to promote rapid burning of the residual fuel.

From the foregoing it will be seen that the present invention provides a combustion apparatus which is relatively simple in construction and operation and is otherwise well adapted for its intended purpose.

What is claimed as new is:

1. In combustion apparatus, in combination,

an elongated casing for air under pressure and comprising front and rear end walls, an openended tubular member arranged within the casing with its front end spaced from the front end wall of the casing to provide an air space thererelatively short open-ended shell arranged within'the casing with its rear end within and radially spaced from the front end of the tubular member to provide an annular air inlet to the latter and with its front end in relatively close proximity for moving said shell in a direction towards and from the front end Wall of the casing to vary the effective inlet area of the air gap therebetween,

, and the front end wall of the air casing having a firing opening in line with the front end of said shell.

2. In combustion apparatus, in combination, an elongated casing for air under pressure and comprising front and rear end walls, an openended tubular member arranged within the casing with its front end spaced from the front end wall of the casing to provide an air space therebetween and with its rear end extending out of the casing through the rear end wall thereof, a relatively short open-ended shell arranged within the casing with its rear end within and radially spaced from the front end of the tubular member to provide an annular air inlet to the latter and with its front end in relatively close proxlrnity to the front end wall of the casing to provide a relatively restricted air gap therebetween, a damper in front of the annular air inlet to said tubular member to vary the effective inlet area of the same, means mounted'on the front end wall of the air casing for adjusting said damper,

and the front end wall of the casing having a firing opening in line with the front end of said shell.

3. In combustion apparatus, in combination, an elongated casing for air under pressure and to the front end wall of the casing to provide a restricted air gap therebetween, the air casing being circular in cross section and having in its side wall adjacent its rear end wall a tangential inlet for air under pressure so that the air on entering said casing tends to whirl therein during its flow towards the front end wall thereof. and the front end wall of the casing having a firing opening in line with the front end wall of said shell.

4. In combustion apparatus, in combination, a casing for air under pressure and comprising front and rear end walls, an open-ended tubular member arranged within the casing with its front end spaced from the front end wall thereof to provide an air space therebetween and with its rear end extending out of the casing through the rear end wall thereof, a relatively short openended shell arranged within the casing with its rear end within and radially spaced from the front end of the tubular shell to provide an annular air inlet to the latter and with its front end in relatively close proximity to the front end wall of the casing to provide a relatively restricted air gap therebetween, an axially adjustable annular damper betweensaid shell and tubular member for varying the effective inlet area of the annular air inlet, a slidable member carriedby the tubular member for supp orting said shell, means for moving the slidable member in a direction towards and from the front end wall of the air casing, the walls of the shell converging towards the front end wall of the casing whereby the front end of the shell is substantially smaller than its rear end, and the front end wall of the casing having a firing opening in line with the front end of said shell.

CHARLES C. OWEN.

' file of this patent:

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